1 files changed, 12 insertions, 8 deletions

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 7066fc5bf48a..dd6ad8445608 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -65,8 +65,8 @@ static int handle_set_clock(struct kvm_vcpu *vcpu)
 static int handle_set_prefix(struct kvm_vcpu *vcpu)
 {
         u64 operand2;
-        u32 address = 0;
-        u8 tmp;
+        u32 address;
+        int rc;
 
         vcpu->stat.instruction_spx++;
 
@@ -80,14 +80,18 @@ static int handle_set_prefix(struct kvm_vcpu *vcpu)
                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 
         /* get the value */
-        if (get_guest(vcpu, address, (u32 __user *) operand2))
-                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+        rc = read_guest(vcpu, operand2, &address, sizeof(address));
+        if (rc)
+                return kvm_s390_inject_prog_cond(vcpu, rc);
 
-        address = address & 0x7fffe000u;
+        address &= 0x7fffe000u;
 
-        /* make sure that the new value is valid memory */
-        if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
-           (copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1)))
+        /*
+         * Make sure the new value is valid memory. We only need to check the
+         * first page, since address is 8k aligned and memory pieces are always
+         * at least 1MB aligned and have at least a size of 1MB.
+         */
+        if (kvm_is_error_gpa(vcpu->kvm, address))
                 return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 
         kvm_s390_set_prefix(vcpu, address);